Re: [PATCH], Add IEEE 128-bit floating point to PowerPC, patch #1

[Michael Meissner <meissner at linux dot vnet dot ibm dot com>]

On Tue, Jun 02, 2015 at 05:55:10PM +0000, Joseph Myers wrote:
> Is the use of FRACTIONAL_FLOAT_MODE to avoid iterations over 
> floating-point modes including these modes when they shouldn't, as 
> discussed previously?
> 
> If so, how do you deal (in subsequent patches?) with iterations that 
> *should* include these modes?  In particular, where libgcc uses 
> __LIBGCC_<mode>_* macros predefined with -fbuilding-libgcc in an 
> interation in c-cppbuiltin.c, how do you handle getting the relevant 
> information in libgcc to build applicable libgcc functions for these 
> modes?  (I'm presuming that you do want complex arithmetic to work for 
> both 128-bit types, for example, although you won't want them to be used 
> for intermediate conversions in libgcc operations on other types.)

I have a catch-22 situation.  We can't really do the glibc stuff until we have
the compiler.  Right now, I use a makefile on libgcc/config/rs6000 that copies
the various TF files and modifies it for KF files.

After we get the basic support in, we can then start tackling glibc.  It may be
when we get to doing the work in glibc itself, we will need to make further
modifications.  However, in order for the glibc people to start, I need the
basic support in the compiler in the tree.

-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.vnet.ibm.com, phone: +1 (978) 899-4797